SymbolicCompare

A comparison of two symbolic expressions.

Declaration

Syntax

SymbolicCompare(expr left, cmpop op, expr right, ttype type,
    expr? value)

Arguments

Argument	Description
left	the left operand.
op	the comparison; see cmpop.
right	the right operand.
type	the logical type of the result.
value	the compile time value of the expression, when the frontend could fold it; nil otherwise.

Return values

The value of the expression.

Description

Symbolic expressions are LPython’s interface to a computer algebra system, and comparing two of them asks whether the expressions are equal as expressions, not whether they have equal numeric values.

Examples

(SymbolicCompare
  :left (Var
    :v (SymbolRef 1 "s")
  )
  :op :Eq
  :right (Var
    :v (SymbolRef 1 "s")
  )
  :type (Logical
    :kind 4
  )
  :value nil
)

It comes from this complete ASR text document:

(TranslationUnit
  :symtab (SymbolTable
    :id 0
    :symbols {
      "main" (Program
        :symtab (SymbolTable
          :id 1
          :symbols {
            "p" (Variable
              :parent_symtab 1
              :name "p"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (Logical
                :kind 4
              )
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
            "s" (Variable
              :parent_symtab 1
              :name "s"
              :dependencies []
              :intent :Local
              :symbolic_value nil
              :value nil
              :storage :Default
              :type (SymbolicExpression)
              :type_declaration nil
              :abi :Source
              :access :Public
              :presence :Required
              :value_attr false
              :target_attr false
              :contiguous_attr false
              :bindc_name nil
              :is_volatile false
              :is_protected false
              :pass_attr :NotMethod
              :self_argument nil
              :codims []
            )
          }
        )
        :name "main"
        :dependencies []
        :body [
          (Assignment
            :target (Var
              :v (SymbolRef 1 "p")
            )
            :value (SymbolicCompare
              :left (Var
                :v (SymbolRef 1 "s")
              )
              :op :Eq
              :right (Var
                :v (SymbolRef 1 "s")
              )
              :type (Logical
                :kind 4
              )
              :value nil
            )
            :overloaded nil
            :realloc_lhs false
            :move_allocation false
          )
        ]
      )
    }
  )
  :items []
)

See Also

SymbolicExpression, IntegerCompare